1. Field of the Invention
The invention relates to an automotive milling machine, a method for discharging milled material, as well as a road or ground working unit.
2. Description of the Prior Art
With an automotive milling machine, it is known to discharge the milled material onto no less than one transport vehicle comprising a loading surface.
The milling machine comprises a controller for the travelling and milling operation, as well as a working drum for the milling of, for example, a road pavement. A transport conveyor device, for example, a transport conveyor device comprising no less than one transport conveyor, is present in front of or behind the working drum as seen in the direction of travel. The transport conveyor device comprises a discharge end at which the milled material is discharged onto the loading surface of the no less than one transport vehicle via a flight path in the form of a parabolic trajectory attributable to the conveying speed. The last or single transport conveyor of the transport conveyor device as seen in the direction of transport may be slewed sideways, relative to the longitudinal axis of the milling machine, under a specifiable slewing angle to the left or right and may be adjustable in height via a specifiable elevation angle. In addition, the conveying speed of the transport conveyor may be adjustable.
In practical operation, problems arise in coordinating the milling machine with the transport vehicle.
With a forward-loading milling machine, for example, the milled material is discharged towards the front onto the transport vehicle driving ahead. The operator of the milling machine needs to signal to the vehicle driver of the transport vehicle as to when the transport vehicle is to continue moving forward and when it is to stop. This leads to problems because the operator basically needs to concentrate on the milling process and at the same time needs to avoid a collision with the transport vehicle driving ahead. The information is usually communicated by means of sounding a horn so that, as soon as the vehicle driver of the transport vehicle hears the horn sounding, the transport vehicle is moved forward by a certain distance. In this context, a problem arises in the situation where the vehicle driver of the transport vehicle fails to hear the horn alert or if another vehicle driving past emits a horn alert. DE 10 2009 041 842 A (U.S. Pat. No. 8,979,424) addresses these problems. The following problems may arise: If the vehicle driver fails to hear the horn alert, and if the same does not drive the transport vehicle forward, this may cause a collision of the slewable transport conveyor of the transport conveyor device with the transport vehicle, or the operator of the milling machine needs to stop the continuous milling process.
If another vehicle driving past emits a horn alert, the vehicle driver of the transport vehicle may erroneously be of the opinion that he has to stop his vehicle. In this case, there is also the risk of collision.
An additional problem lies in the fact that the operator of the milling machine also needs to deal with loading the loading surface by adjusting the slewing angle, elevation angle and conveying speed of the last or single transport conveyor of the transport conveyor device as seen in the direction of transport and is thus distracted from his actual task of carrying out the milling operation. A correction of the slewing angle may be required, for example, when altering the steering direction of the milling machine.
In case of a rearward-loading milling machine, problems also arise in coordinating the milling machine with the transport vehicle especially as the transport vehicle needs to drive behind the milling machine in reverse travel. An even higher level of stress results for the operator of the milling machine as he needs to control the milling process in forward travel on the one hand, and needs to monitor loading of the transport vehicle behind the milling machine as seen in the direction of travel, needs to control the slewing angle, elevation angle and/or conveying speed of the transport conveyor device, and needs to communicate the necessary information to the vehicle driver on the other.
It is generally known to measure the distance between the milling machine and the transport vehicle by means of ultrasonic measuring systems or other distance measuring systems in order to avoid collisions between the milling machine and the transport vehicle. It is a problem in this context that the different transport vehicles do not have a uniform reference surface which the distance measurement could refer to. A different height of the rear wall of the transport vehicles and a different incline of the transport conveyor, in conjunction with different slewing angles of the transport conveyor, lead to collisions of the transport conveyor with the rear wall at entirely different distances between the milling machine and the transport vehicle. Basically, there is the problem that a sensor can only be aligned to non-clearly defined reference surfaces of different transport vehicles with considerable difficulty. Further problems exist if the transport vehicle is not aligned rectilinearly with the milling machine, or the transport container of the transport vehicle exhibits a slanting or, in any case, non-vertical rear wall. Distance measuring systems fail in particular if the transport vehicle is moved at a lateral offset to the milling machine and the transport conveyor can collide with a corner of the container.